Sonic Chaos (May 17, 1993 prototype)

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Title Screen
Sonic Chaos (May 17, 1993 prototype)
Build date May 17, 1993
Dump status Released
Dumped by drx
Released by drx
File release date November 2, 2019
Origin EPROMs
Lot Sonic Month 2019
Labels GG SONIC CHAOS # 17/5
Dump method True-USB PRO GQ-4X
Ownership drx (2019-Present)
Game Sonic Chaos
System Game Gear
Genre Platform
Final build JP Sep 7, 1993
EU Sep 1, 1993
US Sep 1, 1993
Release date JP Nov 19, 1993
EU Nov 23, 1993
US Nov 25, 1993
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A prototype of Sonic Chaos (also known as Sonic & Tails in Japan) for the Sega Game Gear.


The Cutting Room Floor research
  • Near the top of the ROM at offset 0xC0, the following string can be found: "MS SONIC.THE.HEDGEHOG.3 Ver0.00 1993/02/01 @SEGA/Aspect Co.,Ltd".
  • The fourth EPROM in the set lacks data, so it goes unused.
  • The build lacks an intro sequence.
  • The entire game lacks sound at this point.
  • The title screen is slightly different.
  • The player select menu uses simple text on a blue background.
  • A zone select is activated by default after choosing your character.
  • Turquoise Hill Zone is mispelled "Turquise Hill Zone" in the zone select.
  • There are no level title cards.
  • Both Sonic & Tails' sprites are completely different, with both being modeled after their Sonic 2 (Mega Drive) sprites.
  • Each stage seems to contain layout differences.
  • The Game Over screen just uses text on a blue background.
  • Special stages don't seem to be implemented.
  • The Pogo Spring shoes do not seem to be implemented.
  • The life counter uses a single digit instead of two like the final version.
  • Holding the "B" button down will allow you to no-clip through the level. If the player moves through an enemy while no-clipping, they'll receive damage when they return to normal mode.
  • While the player can drop rings from damage, the rings won't be removed from their ring count.
  • The end level sign posts are different. In the prototype, the sign posts feature Sonic before and after you run past them. In the final, the sign posts start with Robotnik and end with either a Flicky or exclamation mark.
  • The score tally screen hasn't been resized for the Game Gear version's resolution.
  • Turqoise Hill Zone uses the same palette as the Sega Master System version.
  • Gigalopolis Zone's boss uses five balls instead of three. The stage's palette changes when the boss appears.
  • Sleeping Egg Zone loads Mecha Green Hill Zone's art instead. In the prototype, it uses a pink background instead of a green (Master System) or a peach (Game Gear) colored one.
  • Sleeping Egg Zone Act 1/2 cannot be completed as there is no sign post.
  • The background palette turns completely white when you encounter Sleeping Egg Zone's boss.
  • Mecha Green Hill Zone's boss climbs over a bit like the Sega Master System version.
  • The background in Aqua Planet Zone is completely different. In the prototype, the player is inside a cavern while the final version has the player outside.
  • None of Aqua Planet Zone's acts can be completed as each act lacks a sign post. Each act mirrors the layout of the first.
  • Aqua Planet Zone's palette is greyscale in Act 2 and 3.
  • There is no boss at the end of Aqua Planet Zone Act 3.
  • Electric Egg Zone lacks sign posts at the end of each act.
  • Aqua Planet Zone's boss is featured at the end of Electric Egg Zone Act 2 for some reason. The game soft locks after you defeat it.
  • There is no boss at the end of Electric Egg Zone Act 3.
  • The ending has not been implemented yet.




File Archive Contents

File Type Date Size SHA-1
Sonic Chaos (May 17, 1993 prototype).gg File 2019-09-07 22:07:23 512 KB 77294880735369d09f2688784d85cdf3e80fa8a3


00007ff0 54 4d 52 20 53 45 47 41 ff ff f9 06 ff ff ff 4f TMR SEGA.......O


See also